Headcut Analysis for Off-Channel Gravel Pits in Arid Environments

Freeman, Gary E.; ,

Headcut Analysis for Off-Channel Gravel Pits in Arid Environments

by Gary E. Freeman, P.E.,

Document Type: Proceeding Paper

Part of: Critical Transitions in Water and Environmental Resources Management

Abstract:

The study focuses on a large gravel pit located adjacent to the Santa Cruz River between the confluences with the Rillito and Canada del Oro rivers in Tucson, Arizona. These gravel pits are large with depths on the order of 100 feet and are immediately adjacent to the surrounding streams. The berms along the pits are not protected and would be subject to erosion due to the flows in the rivers. Different failure scenarios were considered and the locations of possible pitwall failures were identified. The various factors influencing the headcut distance were identified and the methodology previously developed for headcut analysis of in-stream gravel pits were modified to account for the near channel pit. While the width of the pit is one of the major significant factors for the in-stream pits, the use of the pit width vs the channel width can lead to widely varying answers. Another important factor is the time of failure with respect to the flow hydrograph of the event. Methodology and results of the analysis will be presented.

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